The positions of the first and the sixth digits in the number 3597280164 are interchanged. Similarly, the positions of the second and the seventh digits are interchanged, and so on. Which of the following will be the fourth digit from the right end after the rearrangement?

According to question,
In a row of boys Akash is fifth from the left
Left 1 - 2 - 3 - 4 - Akash - 6 - 7 - 8 - 9 - 10 - 11 - 12 .................................................................................................................. Right
If Akash is twenty-fifth from the right then
Left 1 - 2 - 3 - 4 - Akash - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 -14 - 15 -16 -17 -18 -19 - 20- 21- 22 - 23- 24- 25 -26 -27 -28 - 29 Right
Nikhil is eleventh from the right.
Left 1 - 2-3 -4 - Akash - 6 -7- 8- 9-10 -11-12- 13-14- 15 -16-17-18 - Nikhil -20-21-22 - 23 - 24 - 25-26 -27- 28- 29 Right

There are (25 ? 11? 1) = 13 boys between Akash and Nikhil.

According to question,
If the positions of the first and the fifth digits of the number 83721569 are interchanged.
After interchange the new number = 13728569
similarly, the positions of the second and the sixth digits are interchanged.
Again after interchange the new number = 15728369

New arrangement of numbers is as follows: 15728369
Hence, third number from right end is 3.

According to the question,
Rajnish is older than Rajesh and Raman.
Rajnish > Rajesh, Raman..........(i)
Ramesh is older than Rajesh but younger than Rajeev.
Rajeev > Ramesh > Rajesh........(ii)
Raman is older than Rajeev.
Raman >Rajeev.......................(iii)
Combining all, we get
Rajinish > Raman > Rajeev > Ramesh > Rajesh

According to question,
Fifteen children are standing in a row facing north.
Left Side Position 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, 15th Right Side position
Ravi is is eighth from the left end.
Left Side Position 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, 15th Right Side position
......................................................................................Ravi
Ravi is to the immediate left of Prabha.
Left Side Position 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, ........10th, 11th, 12th, 13th, 14th, 15th Right Side position
......................................................................................Ravi, Prabha
Arjun is second from the right end.
Left Side Position 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, ........10th, 11th, 12th, 13th, 14th, 15th Right Side position
......................................................................................Ravi, Prabha........................................Arjun

8th, 9th, 14th
Ravi Prabha Arjun

Let us assume the number of boys in school be B.
Then number of girls in school = 2B
According to question,
B + 2B = 180
3B = 180
B = 180/3 = 60
Number of boys = 60
Number of girls = 120
Rupesh (a boy) ranked 34^th from top and 18 girls are ahead of Rupesh.
Number of boys after the rank of Rupesh = 60 ? 16 = 44

Total students = [ First position of Ganesh + Second position of Rajan ] ?1
Total students = [12 + 20] ? 1 = 31

Number of persons between Vijay and Jack = 48 ? (14 + 17) = 17
Now, Mary lies in middle of these 17 persons i.e, at the eighth position.
So, number of persons between Vijay and Mary = 7.

After exchanging positions, Bhusan becomes fifteenth instead of seventh from the left, it means there are 7 students between them. So Motilal's position from the right will become twelfth. [i.e., (15 ? 7) + 4 = 12]

The possible date of birth of Ana according to Adi are 21st and 22nd September. But according to his father Ana's date of birth should be 22nd and 23rd September. Now after both conclusion there is 22nd September common date, so answer is that (b).

Failed Students
= [ Total students ] ? [ (Anmol's position from upwards) + (Anmol's position from downwards) ? 1 ]
= 45 ? [(11 + 15) ? 1] = 20